Influence of mandibular third molar surgical extraction on the periodontal status of adjacent second molars

The periodontal health distal of second molars (M2) is often compromised because of third molar (M3) impactions. The aim of this study was to evaluate healing and periodontal status of mandibular M2 after M3 surgical extraction.

Eighty-nine consecutive patients with 89 asymptomatic M3 who needed surgical extraction of one fully- or semi-impacted M3 entered this study. Clinical measurements, probing pocket depth (PPD), clinical attachment level (CAL), plaque index (PI), gingival index (GI), and bleeding on probing (BOP), were compared for M2 at baseline (T0) and 6-months (T1) postsurgical extraction. Multiple logistic regression analysis assessed different risk factors for postoperative changes of periodontal parameters.

Six-month M2 PPD improved at disto-vestibular (T0-5.2/T1-3.0 mm) and disto-lingual (T0-5.4/T1-3.2 mm) sites. The average attachment gains at T1 were 1.9 and 2 mm, respectively (P < 0.05). BOP, PI, and GI showed significant clinical improvements after extractions. Fifty-three out of 72 (73.6%) M2 presenting a PPD ≥ 4mm at baseline healed at 6 months recall without periodontal pockets. Older age (mean 55 years, SD 16.7; range 26 to 81) and mean distal PPD at baseline of 7 mm was more likely to be associated with PPD ≥ 4 mm 6 months postextraction (P < 0.05). Past history of periodontitis patients were 41 times more likely to present PPD ≥ 4 mm after healing (OR = 41.4; 95% CI = 10.9 to 156.5, P < 0.05).

Mandibular M3 extractions seem to improve overall periodontal health distal of M2. History of periodontitis, preoperative deep pockets and older age are independent risk factors for poorer healing and residual pockets after M3 surgical extraction.